In general, vehicles have been provided with safety equipments such as seat belts and airbags, inter alia, for the purpose of protecting vehicle occupants as a result of a vehicle crash (including overturn and rollover). However, depending on a longitudinal position of a seat, on which an occupant has actually been seated, or on a degree to which a seat back is reclined, these safety equipments do not always perform to a sufficient stand.
In the light of the foregoing, recent requirements have led to maintaining factors within a vehicle, such as seat posture, in conditions of a high level of safety in anticipation of a vehicle impact (including overturn and rollover). For example, JP2000-62559A, especially as described in pages 3 and 4, and as illustrated in FIG. 3, discloses an occupant protection device for vehicle in the event of a vehicle rollover. In this system, when an occurrence of a vehicle rollover is detected, a seat belt is tightened around a vehicle occupant, whereby the occupant is constricted within the seat. Moreover, in this system, when a window is open, the window is closed, and the occupant is prevented from falling out of the vehicle.
However, in order to actually prepare a vehicle for the eventuality of a vehicle crash, it is necessary to operate at the same time, by means of actuators, a considerable number of components such as an occupant seat, a seat belt and a vehicle window. In such circumstances, a considerable number of actuators such as motors are all driven together at the same time. A waveform chart illustrated in FIG. 11 explains transitions in degrees of electric power consumed in the course of driving motors that can operate components such as a sunroof, a side window of a vehicle seat A, a seat sliding mechanism of the vehicle seat A and a seat reclining mechanism of the vehicle seat A. In general, a motor requires a great amount of electric power when it is initially driven, and is supplied with a great amount of inrush current. Such inrush current is depicted by a current waveform of an impulse shape, as shown in the waveform chart illustrated in FIG. 11.
As described above, when a considerable number of motors are driven at the same time in response to early warning of a vehicle crash, the considerable number of motors are supplied with inrush current at the same time. In such a case, a high current may be supplied to all wires for feeding electric current to these motors. As a result, a level of voltage may drop, due to resistance in the wires, or due to deficiencies in the amount of electric current that a battery can supply to the motors. The motors may then not be able to generate torque at a sufficient level, and the components operated by the motors may not be able to operate in the desired manner.
The present invention has been made in view of the above circumstances, and provides an occupant protection device for vehicle, according to which conditions inside a vehicle, such as seat postures and safety devices, can be brought to a high level of safety quickly, and thereafter maintained effectively at a high level of safety.